Device for securing a cable to the concrete platform of a bridge, and bridge equipped with such devices

ABSTRACT

This invention relates to a device for fastening a guy to a concrete bridge deck. A metal plate is abutted against the horizontal surface of the deck and retained there with pre-stressing cables at its top surface and an extension which protrudes downward into the deck from its bottom surface. An anchoring device is mounted on the upper surface of the plate. It may be positioned to keep the guy in a plane parallel to the plate and do not require that the cables pass through the deck. The deck may have spaced bearing surfaces that are angled and/or are parallel to one another and support anchoring devices that keep the cables running in different directions from one another.

The present invention relates to a device for fastening a guy to aconcrete deck of a bridge, especially of a bridge with so-called"radiating" guying, in which a series of guys connects uniformly spacedpoints of the deck to the top of a supporting mast.

According to the conventional techique, a guy is fastened to the deck byensuring that the guy passes through the deck, usually in the region ofa longitudinal boom, in order to carry, on the opposite face of thedeck, end retention means which bear on this lower face of the deck.

When the deck is made of reinforced concrete, the presence of the tubescontaining the guys, which are at inclinations varying uniformly fromone end of the bridge to the other, the angle with the horizontaldecreasing in proportion to the distance from the mast, disturbs thereinforcing device to a considerable extent, thus making it necessary toproduce the latter with particular care which is incompatible withhigh-speed production or with prefabrication on a relatively industrialscale.

The object of the invention is to overcome this disadvantage and toprovide a fastening device which does not make it necessary to changethe reinfoarcing planes in the region of each fastening of the guy andwhich consequently makes it possible to achieve faster construction lessliable to risks of error.

To achieve this result, the invention provides a device for fastening aguy to a concrete deck of a bridge which comprises:

a metal plate, one face of which is designed to come up against a planebearing surface of the deck, this face carrying at least one projectioncapable of penetrating into a cavity of the deck, to prevent the plateand the said plane bearing surface from sliding one relative to theother,

means for fastening the end of the guy, these means being carried bymountings fixed to the face of the plate opposite that designed to cometo bear against the deck, and

prestressing cables or ties capable of keeping the plate bearing againstthe plane surface of the deck, these cables or ties bearing on the sideof the deck opposite that carrying the said plane surface.

Preferably, the projection and/or the cavity have a form of revolutionabout an axis perpendicular to the plane of the plate of the planebearing surface, to allow the device to be oriented according to thedirection of the guy.

In an advantageous embodiment, the projection contains retention meansfor one of the said prestressing cables or ties.

According to a first embodiment, the fastening means are intended tomake it possible to maintain the guy at a non-zero inclination relativeto the plate. This arrangement is used advantageously ii the said planebearing surface of the deck is a horizontal surface and if theprestressing cables or ties pass downwards through the deck so as tocome to bear on a horizontal surface extending in the opposite directionof the said deck.

According to another embodiment, the anchoring means are intended tomake it possible to keep the guy in a plane parallel to that of theplate. This second embodiment is especially advantageous if the planebearing surface of the deck is carried by one of the edges of the deckand has, relative to the vertcal, the same angle as the sheet of whichthe guy which the device is to hold forms part, and if the prestressingcable or tie passes through the deck in a direction which as a whole istransverse and approximately horizonta..

The invention also provides a guyed bridge which is equipped withdevices such as those described above, and the particular feature ofwhich is that the deck carries, at regular intervals, plane bearingsurfaces oriented parallel to one another, and the plane bearingsurfaces support fastening devices which maintain the cables atdifferent directions from one another.

The invention will now be explained in more detail with reference topractical examples illustrated by means of the drawings of which:

FIG. 1 is an elevation view of a guyed bridge for which the deviceaccording to the present invention is suitable.

FIG. 2 is a longitudinal section through a first embodiment of a deviceaccording to the invention.

FIG. 3 is a section through the device of FIG. 2 in a planeperpendicular to the guy.

FIG. 4 is a view of the device of FIG. 2 in a longitudinal direction.

FIG. 5 is a view of a second embodiment of the fastening deviceaccording to the invention in a transverse direction.

FIG. 6 is a partial cross-section through a deck possessing the deviceof FIG. 5.

FIG. 7 is a longitudinal section of the device in an inclined planecontaining the guy.

FIG. 8. is a section through the device perpendicular to the directionof the guy.

FIG. 1 illustrates a bridge, the deck 1 of which rests on abutments 2 atone end and is supported by guys 3 which connect successive points ofthe deck to the top 4 of a mast 5 mounted on piers 6 resting on theground 7.

FIG. 2 shows a fastening device according to the invention mounted onthe horizontal upper face of a deck 1.

The device comprises a plate 10 carrying, in its lower part, afrustoconical projection 11 which penetrates into a corresponding cavityof the upper face of the deck 1. On the upper face of the plate 10,T-section bars 12, 13 are secured obliquely to the said plate 11, theirgeneral direction forming with the torizontal an angle equal to that ofthe guy 3 which the device is intended for retaining. The end of the gcy3 passes through a fastening piece 14 welded to the bars 12 and 13 andbears on this piece 14 by means of an endpiece 15. Prestressing ties 16pass through the entire thickness of the deck 11 and, by means of screws17, 18, clamp the plate 10 firmly against the deck. The tensile forcesexerted by the tie 3 can be broken down into a vertical componentabsorbed by the ties 16 and a horizontal component which is transmittedto the deck by the projection 11 and as a result of the friction of theplate 10 against the horizontal bearing surface prcvided on the deck.

FIGS. 5 to 8 show another embodiment. The deck, on its outer edge ormargin, has a bearing surface 20 directed longitudinally and slightlyobliquely relative to the vertical. The bearing surface 20 as a whole iscircular. The deck 1, since it is relatively thin, has an extrathickness 21 for receiving this bearing surface. The actual fasteningdevice comprises a c rcular plate 22 which comes to bear on the surface20 and which, in its part facing the deck, carries a frustoconicalprojection 23 which is hollow and which comes to rest in a likewisefrustoconical cavity 24 provided at the centre of the bearing surface20. The plate 22, on its face opposite the projection 23, carriesmountings consisting of two identical flat bars 25 arrangedperpendicularly relative to the plate 20 and between them forming a kindof fork, between which is accommodated a supporting piece 26, againstwhich bears an end piece 27 fixed to the guy 3. The hollow projection 23serves as a receptacle for the anchoring head of a prestressing cable 28which penetrates into the deck 1 via an oblique passage perpendicular tothe plane of the surface 20. This cable subsequently curves to becomehorizontal and passes through the entire width of the deck, in order tobe anchored to a similar device located on the opposite nargin of thedeck.

It will be appreciated that, to install the guys, the device must beoriented by pivoting the plate about the axis of the cavity 24, until itis brought into the right direction. The inclination of the surfaces 20relative to the horizontal is that of all the guys of the same sheet ofcables supporting the edge of the deck. It is therefore sufficient,during the construction of the bridge, to provide bearing surfaces 20identical to one another at the intended locations on the deck and eachtime orient the plate 22 to obtain a perfect alignment of the fasteningdevice with the cables.

With the arrangement of FIGS. 2 to 4, it is necessary to ensure that theorientation of the mountings 12 and 13 is changed for each fasteningpoint. This complication is compensated because there is no need to havea prestressing cable passing through the entire deck. It is possible,moreover, to provide an articulated connection between the mountings 12and 13 and the fastening piece 14, thus making it possible to use thesame piece for a certain number of guys at this particular moment, atleast within certain limits.

I claim:
 1. Device for fastening a guy to a concrete deck of a tridge,characterized in that it comprises:a metal plate, one face of which isdesigned to come to bear against a plane bearing surface of the deck,this face carrying at least one projection capable of penetrating into acavity of the deck, to prevent the plate and the said plane bearingsurface from sliding one relative to the other, means for fastening theend of the guy, these means being carried by mountings fixed to the faceof the plate opposite that designed to come to bear against the deck,and prestressing cables or ties capable of keeping the plate bearingagainst the plane surface of the deck, these cables or ties bearing onthe side of the deck opposite that carrying the said plane surface. 2.Device according to claim 1, characterized in that the projection and/orthe cavity have a form of revolution about an axis perpendicular to theplane of the plate or of the plane bearing surface, to allow the deviceto be oriented according to the direction of the guy.
 3. Deviceaccording to claim 1, characterized in that the projection contains theretention means for a prestressing cable or tie.
 4. Device according toclaim 1, characterized in that the fastening means are intended to makeit possible to maintain the guy at a non-zero inclination relative tothe plate.
 5. Device according to claim 4, characterized in that thesaid plane bearing surface of the deck is a horizontal surface, and theprestressing cables or tes pass downwards through the deck, so as tobear on a horizontal surface extending in the opposite direction of thesaid deck.
 6. Device according to claim 1, characterized in that thefastening means are intended to make it possible to keep the guy in aplane parallel to that of the plate.
 7. Device according to claim 6,characterized in that the plane bearing surface of the deck is carriedby one of the edges of the deck and has, relative to the vertical, thesame angle as the sheet of which the gJy which the device is to holdforms part, and the pre-stressing cable or tie passes through the deckin a direction which as a whole is transverse and approximatelyhorizontal.
 8. Guyed bridge equipped with devices according to claim 1,characterized in that the deck carries, at regular intervals, planebearing surfaces oriented parallel to one another, these plane bearingsurfaces supporting the anchoring devices which maintain the cables atdifferent directions from one another.